A read-modify-write (RMW) technique has hitherto been adopted to write data on a disk from and on which data is read out and written in units of sectors. In the RMW, the write data to be written on the disk is processed for the writing in units of sectors and then is written on the disk. The read-modify-write is a technique to read out data from a disk in sectors of an integer number such that the sectors include storage areas into which the write data is to be written, rewrite the data in the storage areas within the read out sectors to the write data, and write the rewritten sectors back into the disk.
Related techniques include, for example, a technique in which, upon reception of data requiring an RMW operation, the start of the RMW operation is delayed for within the time which a disk takes to rotate once and which is substantially the same as the time required for controlling the RMW operation. Upon reception of the remaining data to be sequentially written, the previously received data and the currently received remaining data are written together to one sector without the RMW operation. The related techniques also include a technique in which a multi-planar array of partition distribution data is created, as a collection of all possible maximum and minimum sub-cache sizing, from least recently used (LRU) lists of referenced objects and traces of objects, and a dynamic programming heuristic is applied to the multi-planar array.
Related techniques are disclosed in, for example, Japanese Laid-open Patent Publication No. 2010-267345 and Japanese Laid-open Patent Publication No. 06-161898.
However, with the techniques described above, in writing of write data into a disk in units of sectors, the data used for processing the write data is read out from the disk to disadvantageously increase the time for a writing process of the write data.